diff options
Diffstat (limited to 'block/blk-core.c')
| -rw-r--r-- | block/blk-core.c | 28 |
1 files changed, 21 insertions, 7 deletions
diff --git a/block/blk-core.c b/block/blk-core.c index 3508751c779..034cbb2024f 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1203,18 +1203,32 @@ static bool bio_attempt_front_merge(struct request_queue *q, return true; } -/* - * Attempts to merge with the plugged list in the current process. Returns - * true if merge was successful, otherwise false. +/** + * attempt_plug_merge - try to merge with %current's plugged list + * @q: request_queue new bio is being queued at + * @bio: new bio being queued + * @request_count: out parameter for number of traversed plugged requests + * + * Determine whether @bio being queued on @q can be merged with a request + * on %current's plugged list. Returns %true if merge was successful, + * otherwise %false. + * + * This function is called without @q->queue_lock; however, elevator is + * accessed iff there already are requests on the plugged list which in + * turn guarantees validity of the elevator. + * + * Note that, on successful merge, elevator operation + * elevator_bio_merged_fn() will be called without queue lock. Elevator + * must be ready for this. */ -static bool attempt_plug_merge(struct task_struct *tsk, struct request_queue *q, - struct bio *bio, unsigned int *request_count) +static bool attempt_plug_merge(struct request_queue *q, struct bio *bio, + unsigned int *request_count) { struct blk_plug *plug; struct request *rq; bool ret = false; - plug = tsk->plug; + plug = current->plug; if (!plug) goto out; *request_count = 0; @@ -1282,7 +1296,7 @@ void blk_queue_bio(struct request_queue *q, struct bio *bio) * Check if we can merge with the plugged list before grabbing * any locks. */ - if (attempt_plug_merge(current, q, bio, &request_count)) + if (attempt_plug_merge(q, bio, &request_count)) return; spin_lock_irq(q->queue_lock); |